/*
  SHA-1 in C By Steve Reid <steve@edmweb.com> 100% Public Domain

  Test Vectors (from FIPS PUB 180-1)
  "abc"
        A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D
  "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"
        84983E44 1C3BD26E BAAE4AA1 F95129E5 E54670F1
  A million repetitions of "a"
        34AA973C D4C4DAA4 F61EEB2B DBAD2731 6534016F
*/

/* 在x86平台上需要定义下面的宏 */
#define LITTLE_ENDIAN

/* #define LITTLE_ENDIAN * This should be #define'd if true. */
/* #define SHA1HANDSOFF * Copies data before messing with it. */

#include <stdio.h>
#include <string.h>
#include "sha1.h"

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
#ifdef LITTLE_ENDIAN
#define blk0(i) (block->l[i] = (rol(block->l[i],24)&0xFF00FF00) \
    |(rol(block->l[i],8)&0x00FF00FF))
#else
#define blk0(i) block->l[i]
#endif
#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
    ^block->l[(i+2)&15]^block->l[i&15],1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);


/* Hash a single 512-bit block. This is the core of the algorithm. */

void SHA1Transform(unsigned long state[5], unsigned char buffer[64])
{
  unsigned long a, b, c, d, e;
  typedef union {
    unsigned char c[64];
    unsigned long l[16];
  } CHAR64LONG16;
  CHAR64LONG16* block;
#ifdef SHA1HANDSOFF
  static unsigned char workspace[64];
  block = (CHAR64LONG16*)workspace;
  memcpy(block, buffer, 64);
#else
  block = (CHAR64LONG16*)buffer;
#endif
  /* Copy context->state[] to working vars */
  a = state[0];
  b = state[1];
  c = state[2];
  d = state[3];
  e = state[4];
  /* 4 rounds of 20 operations each. Loop unrolled. */
  R0(a,b,c,d,e, 0);
  R0(e,a,b,c,d, 1);
  R0(d,e,a,b,c, 2);
  R0(c,d,e,a,b, 3);
  R0(b,c,d,e,a, 4);
  R0(a,b,c,d,e, 5);
  R0(e,a,b,c,d, 6);
  R0(d,e,a,b,c, 7);
  R0(c,d,e,a,b, 8);
  R0(b,c,d,e,a, 9);
  R0(a,b,c,d,e,10);
  R0(e,a,b,c,d,11);
  R0(d,e,a,b,c,12);
  R0(c,d,e,a,b,13);
  R0(b,c,d,e,a,14);
  R0(a,b,c,d,e,15);
  R1(e,a,b,c,d,16);
  R1(d,e,a,b,c,17);
  R1(c,d,e,a,b,18);
  R1(b,c,d,e,a,19);
  R2(a,b,c,d,e,20);
  R2(e,a,b,c,d,21);
  R2(d,e,a,b,c,22);
  R2(c,d,e,a,b,23);
  R2(b,c,d,e,a,24);
  R2(a,b,c,d,e,25);
  R2(e,a,b,c,d,26);
  R2(d,e,a,b,c,27);
  R2(c,d,e,a,b,28);
  R2(b,c,d,e,a,29);
  R2(a,b,c,d,e,30);
  R2(e,a,b,c,d,31);
  R2(d,e,a,b,c,32);
  R2(c,d,e,a,b,33);
  R2(b,c,d,e,a,34);
  R2(a,b,c,d,e,35);
  R2(e,a,b,c,d,36);
  R2(d,e,a,b,c,37);
  R2(c,d,e,a,b,38);
  R2(b,c,d,e,a,39);
  R3(a,b,c,d,e,40);
  R3(e,a,b,c,d,41);
  R3(d,e,a,b,c,42);
  R3(c,d,e,a,b,43);
  R3(b,c,d,e,a,44);
  R3(a,b,c,d,e,45);
  R3(e,a,b,c,d,46);
  R3(d,e,a,b,c,47);
  R3(c,d,e,a,b,48);
  R3(b,c,d,e,a,49);
  R3(a,b,c,d,e,50);
  R3(e,a,b,c,d,51);
  R3(d,e,a,b,c,52);
  R3(c,d,e,a,b,53);
  R3(b,c,d,e,a,54);
  R3(a,b,c,d,e,55);
  R3(e,a,b,c,d,56);
  R3(d,e,a,b,c,57);
  R3(c,d,e,a,b,58);
  R3(b,c,d,e,a,59);
  R4(a,b,c,d,e,60);
  R4(e,a,b,c,d,61);
  R4(d,e,a,b,c,62);
  R4(c,d,e,a,b,63);
  R4(b,c,d,e,a,64);
  R4(a,b,c,d,e,65);
  R4(e,a,b,c,d,66);
  R4(d,e,a,b,c,67);
  R4(c,d,e,a,b,68);
  R4(b,c,d,e,a,69);
  R4(a,b,c,d,e,70);
  R4(e,a,b,c,d,71);
  R4(d,e,a,b,c,72);
  R4(c,d,e,a,b,73);
  R4(b,c,d,e,a,74);
  R4(a,b,c,d,e,75);
  R4(e,a,b,c,d,76);
  R4(d,e,a,b,c,77);
  R4(c,d,e,a,b,78);
  R4(b,c,d,e,a,79);
  /* Add the working vars back into context.state[] */
  state[0] += a;
  state[1] += b;
  state[2] += c;
  state[3] += d;
  state[4] += e;
  /* Wipe variables */
  a = b = c = d = e = 0;
}


/* SHA1Init - Initialize new context */

void SHA1Init(SHA1_CTX* context)
{
  /* SHA1 initialization constants */
  context->state[0] = 0x67452301;
  context->state[1] = 0xEFCDAB89;
  context->state[2] = 0x98BADCFE;
  context->state[3] = 0x10325476;
  context->state[4] = 0xC3D2E1F0;
  context->count[0] = context->count[1] = 0;
}


/* Run your data through this. */

void SHA1Update(SHA1_CTX* context, unsigned char* data, unsigned int len)
{
  unsigned int i, j;

  j = (context->count[0] >> 3) & 63;
  if ((context->count[0] += len << 3) < (len << 3)) context->count[1]++;
  context->count[1] += (len >> 29);
  if ((j + len) > 63)
  {
    memcpy(&context->buffer[j], data, (i = 64-j));
    SHA1Transform(context->state, context->buffer);
    for (; i + 63 < len; i += 64)
    {
      SHA1Transform(context->state, &data[i]);
    }
    j = 0;
  }
  else i = 0;
  memcpy(&context->buffer[j], &data[i], len - i);
}


/* Add padding and return the message digest. */

void SHA1Final(unsigned char digest[20], SHA1_CTX* context)
{
  unsigned long i, j;
  unsigned char finalcount[8];

  for (i = 0; i < 8; i++)
  {
    finalcount[i] = (unsigned char)((context->count[(i >= 4 ? 0 : 1)]
                                     >> ((3-(i & 3)) * 8)) & 255);  /* Endian independent */
  }
  SHA1Update(context, (unsigned char *)"\200", 1);
  while ((context->count[0] & 504) != 448)
  {
    SHA1Update(context, (unsigned char *)"\0", 1);
  }
  SHA1Update(context, finalcount, 8);  /* Should cause a SHA1Transform() */
  for (i = 0; i < 20; i++)
  {
    digest[i] = (unsigned char)
                ((context->state[i>>2] >> ((3-(i & 3)) * 8)) & 255);
  }
  /* Wipe variables */
  i = j = 0;
  memset(context->buffer, 0, 64);
  memset(context->state, 0, 20);
  memset(context->count, 0, 8);
  memset(&finalcount, 0, 8);
#ifdef SHA1HANDSOFF  /* make SHA1Transform overwrite it's own static vars */
  SHA1Transform(context->state, context->buffer);
#endif
}

void sha1(unsigned char *src, int srclen, unsigned char *des)
{
  SHA1_CTX context;
  
  SHA1Init(&context);
  SHA1Update(&context, src, srclen);
  SHA1Final(des, &context);
}

/* Convert a number in the [0, 16) range to
   the ASCII representation of the corresponding hexadecimal digit.
   `+ 0' is there so you can't accidentally use it as an lvalue.  */
#define XNUM_TO_DIGIT(x) ("0123456789ABCDEF"[x] + 0)
#define XNUM_TO_digit(x) ("0123456789abcdef"[x] + 0)

void sha1s(unsigned char *src, int srclen, char *des)
{
    int i;
    unsigned char sha1_d[20];
    
    sha1(src,srclen,sha1_d);
    
    for (i = 0; i < 20; i++)
    {
	    *des = XNUM_TO_digit (sha1_d[i] >> 4);
	    des++;
	    *des = XNUM_TO_digit (sha1_d[i] & 0xf);
	    des++;
    }

	  *des = '\0';
}

/*************************************************************/

#ifdef TEST_SHA1
int main(int argc, char** argv)
{
  int i, j;
  SHA1_CTX context;
  unsigned char digest[20], buffer[16384];
  FILE* file;

  sha1s("abc",3,buffer);
  printf("%s\n",buffer);
  sha1s("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
    strlen("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"),buffer);
  printf("%s\n",buffer);

  if (argc > 2)
  {
    puts("Public domain SHA-1 implementation - by Steve Reid <steve@edmweb.com>");
    puts("Produces the SHA-1 hash of a file, or stdin if no file is specified.");
    exit(0);
  }
  if (argc < 2)
  {
    file = stdin;
  }
  else
  {
    if (!(file = fopen(argv[1], "rb")))
    {
      fputs("Unable to open file.", stderr);
      exit(-1);
    }
  }
  SHA1Init(&context);
  while (!feof(file))
  {  /* note: what if ferror(file) */
    i = fread(buffer, 1, 16384, file);
    SHA1Update(&context, buffer, i);
  }
  SHA1Final(digest, &context);
  fclose(file);
  for (i = 0; i < 5; i++)
  {
    for (j = 0; j < 4; j++)
    {
      printf("%02X", digest[i*4+j]);
    }
    putchar(' ');
  }
  putchar('\n');
  exit(0);
}

#endif

